So the looping server crashing axkit.org was caused by libxml2. I had recently run apt-get dist-upgrade, and it had updated my libxml2. However it seems this did "something" that meant that when it came to XSP's parse() section, it locked up good and solid with 100% CPU.
So beware - if you have source installs (e.g. perl modules) and you mix them with RPM's, be careful when you do an upgrade as all hell can break loose.
What a wasted bunch of hours tracking this down